Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 68 users online :: 5 registered, 0 hidden and 63 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

combustion vacuum thaught

A place to ask general spud cannon related questions.
Sponsored 
  • Author
    Message

combustion vacuum thaught

Unread postAuthor: kris » Wed Nov 15, 2006 3:31 pm

ive noticed that when i put the barrel of a mini cannon and fired it, a large amount of water got sucked into the chamber so the same must be happening in large ones (not in water) so it might be a good idea to put on-way valves on the chamber some air can be sucked into the chamber thus inproving shooting distance. its just a thaught.
  • 0


kris
Specialist
Specialist
 
Posts: 45
Joined: Sat Jun 24, 2006 4:44 pm
Reputation: 0

Unread postAuthor: SpudBlaster15 » Wed Nov 15, 2006 6:36 pm

Why not simply install a chamber fan?
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: kris » Wed Nov 15, 2006 6:42 pm

b/c it might still occur, when the explotion pushs out the potato the outside air would want to replace the air that got burned up from the combustion.
  • 0


kris
Specialist
Specialist
 
Posts: 45
Joined: Sat Jun 24, 2006 4:44 pm
Reputation: 0

Unread postAuthor: SpudBlaster15 » Wed Nov 15, 2006 6:53 pm

The vaccum created would not completely replace the combustion products in the chamber, so venting would still be nessesary. A chamber fan can vent an average sized chamber in seconds, so the effect of a one way valve would be negligable.

Can a one way valve withstand the 40+psi generated inside the launcher when combustion occurs?
  • 0

People should not be afraid of their governments. Governments should be afraid of their people.
User avatar
SpudBlaster15
Major General
Major General
 
Posts: 2385
Joined: Wed Oct 18, 2006 11:12 pm
Location: Canada
Country: Poland (pl)
Reputation: 3

Unread postAuthor: zeigs spud » Wed Nov 15, 2006 7:09 pm

yea no real need. just get a chamber fan. Glad your thinking though! :D
  • 0

User avatar
zeigs spud
Colonel
Colonel
 
Posts: 657
Joined: Tue Apr 04, 2006 10:39 pm
Reputation: 0

Unread postAuthor: FiveseveN » Thu Nov 16, 2006 8:03 am

I think he meant to use the pressure difference to further propel the projectile.
In an "ideal" cannon, the pressure behind the projectile would be equal to the one in front of it (atmospheric pressure) when it passes the muzzle.
In real life (spudguns and weapons in general), there's quite a bit of pressure left behind the projectile by the time it leaves the barrel. Due to inertia, the leftover gas propels the projectile for a split second even after it exits the barrel.
By the time the gas would be cool enough to create a vacuum, the projectile would have been long gone.

And, for the record, what happens in water is quite different to what happens in air, as far as our little part of ballistics is concerned.
  • 0

User avatar
FiveseveN
Captain
Captain
 
Posts: 337
Joined: Fri Oct 14, 2005 5:48 am
Location: Nowhere
Reputation: 0

Unread postAuthor: zeigs spud » Mon Dec 11, 2006 5:36 pm

kris wrote:b/c it might still occur, when the explotion pushs out the potato the outside air would want to replace the air that got burned up from the combustion.


god idea glad ur thinkin but really the diffrnce to make a sucsessful one of these that improved distace would only be a foot mabey? the explosion s rapid expansion wich is filling the space of the cannon. the air along with the fuel turns into a plasma (one physical state up from "gas" [like air] in which the molecuels of the element/substance are ionized) any suction which could even potentially cause an effect on the spud acurs after it is lauched clear from the barrel. plus any opening alos the explosions pressure to escape faster another way.

compressed air to fill it make sure that there is in suction would then just be a hybrid.

~Z.S.~
  • 0

User avatar
zeigs spud
Colonel
Colonel
 
Posts: 657
Joined: Tue Apr 04, 2006 10:39 pm
Reputation: 0

Sponsored

Sponsor
 


Unread postAuthor: boilingleadbath » Mon Dec 11, 2006 5:57 pm

If your idea is to relieve the suction created during launch... you don't have to worry about that; most barrrels arn't long enough to notice the effect.

Furthermore, if you did have that problem, it'd be simpler to just shorten the barrel.
  • 0

User avatar
boilingleadbath
Moderator
Moderator
 
Posts: 1642
Joined: Sat Mar 12, 2005 10:35 pm
Location: Pennsylvania, USA
Reputation: 0

Return to General Spud Cannon Related

Who is online

Registered users: Bing [Bot], Google [Bot], Google Adsense [Bot], MSNbot Media, Yahoo [Bot]

Reputation System ©'